1. Field of the Invention
The invention relates to a machine for cutting ribbons from a traveling web of material.
2. Description of the Related Art
There are a number of devices presently known for cutting ribbons from a web of fabric material. However, none of these references satisfactorily solve the problems associated with cutting ribbons with printed patterns from the moving web. When a web of fabric material is printed with several patterns and rolled onto a roller, the web has a tendency to shrink in some spots, stretch in others and shift laterally along the roller. Accordingly, when the web is unrolled, it becomes impossible to align the cutter blades with each of the patterns and cut ribbons without cutting off parts of the printed patterns.
If the web only contains solid colors or random patterns, misalignment of the cutter blades with the patterns on the web due to stretching, shrinking or lateral shifting does not produce visible variations in the cut ribbons. If the printed patterns, however, are not random, then misalignment of the cutter blades with the printed patterns due to stretching, shrinking or shifting of the web results in very noticeable variations in the cut ribbons. Some prior ribbon cutting devices disclosed the use of only one adjustable blade for trimming the salvage, for example, U.S. Pat Nos. 1,792,460; 1,809,619 and 1,835,556 all disclose a single adjustable position blade for use in splitting cloth as it comes off a loom.
Some references disclosed devices which moved all of the cutter blades, as a unit, in order to follow variations in the web. These include: U.S. Pat. No. 868,688 which describes an early device employing a mechanism for moving all of the cutting knives on a loom as a single unit; U.S. Pat. No. 588,844 which discloses another device employing a plurality of rotary knives all carried on the same shaft for cutting strips of bandage material off a wider bolt of fabric; and, U.S. Pat. No. 294,970 which discloses another machine for cutting strips of fabric from material in which a plurality of independently mounted blades are employed for that purpose.
The most recent reference which uses this approach, i.e., moving all of the cutter blades as a unit, is U.S. Pat. No. 4,674,380 which describes an apparatus for cutting ribbons using a plurality of razor blades. In this reference, all of the razor blades are driven as a single unit by a lateral shifting means which includes a flexible and resilient rod interconnecting each of the blade holding means adjacent to the associated razor blade. U.S. Pat. 4,674,380, however, does not discuss or suggest several independent groups of blades which are separately driveable. Also cited in the prosecution of U.S. Pat. No. 4,674,380 are U.S. Pat. Nos. 3,407,690; 3,699,621; 3,877,199 and 4,312,255. Of that group, U.S. Pat. Nos. 3,877,199 and 4,312,255 are of possible relevance in that they disclose means for adjusting individual cutting blades on a machine that has a continuously moving web.
All of the foregoing references, however, suffer from the same drawback, in that all cutter blades adjust as a group to variations in the web. These references thus only solve the problem of lateral shifting of the web. None of the devices disclosed in these references, however, are able to compensate for the frequent stretching and shrinking of the web, resulting in one printed pattern being displaced to some degree in one direction while other printed patterns are simultaneously being displaced to some other degree in other directions. Solving this problem requires the separate adjustment of individual groups of blades in one direction while other groups of blades remain the same or are adjusted to a greater or lessor extent in another direction.